go: lower Go requirement to Go 1.18

.github/workflows/ci.yml

@@ -11,21 +11,52 @@ on:
     - cron: "30 10 * * 0"
 
 jobs:
-  test-windows:
+  test-build:
     strategy:
       fail-fast: false
       matrix:
+        os:
+          - windows-latest
+          - ubuntu-latest
+          - macos-latest
         go-version:
+          - "1.18"
+          - "1.19"
+          - "1.20"
           - "1.21"
           - "1.22"
+          - "1.23"
           - "^1"
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ${{ matrix.go-version }}
+      - name: go build check
+        run: go build ./...
+      - name: go test build check
+        run: go test -run none ./...
+
+  test-windows:
+    strategy:
+      fail-fast: false
+      matrix:
+        go-version:
+          - "1.18"
+          - "1.20"
+          - "1.21"
+          - "oldstable"
+          - "stable"
     runs-on: windows-latest
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
           go-version: ${{ matrix.go-version }}
       - name: mkdir gocoverdir
+        # We can only use -test.gocoverdir for Go >= 1.20.
+        if: ${{ matrix.go-version != '1.18' && matrix.go-version != '1.19' }}
         run: |
           # mktemp --tmpdir -d gocoverdir.XXXXXXXX
           function New-TemporaryDirectory {
@@ -42,8 +73,15 @@ jobs:
           $GOCOVERDIR = (New-TemporaryDirectory -Prefix "gocoverdir")
           echo "GOCOVERDIR=$GOCOVERDIR" >>"$env:GITHUB_ENV"
       - name: unit tests
-        run: go test -v -cover '-test.gocoverdir' "$env:GOCOVERDIR" ./...
+        run: |
+          if (Test-Path 'env:GOCOVERDIR') {
+            go test -v -cover '-test.gocoverdir' "$env:GOCOVERDIR" ./...
+          } else {
+            go test -v ./...
+          }
       - name: upload coverage
+        # We can only use -test.gocoverdir for Go >= 1.20.
+        if: ${{ matrix.go-version != '1.18' && matrix.go-version != '1.19' }}
         uses: actions/upload-artifact@v4
         with:
           name: coverage-${{ runner.os }}-${{ github.job }}-${{ strategy.job-index }}
@@ -57,24 +95,30 @@ jobs:
           - ubuntu-latest
           - macos-latest
         go-version:
+          - "1.18"
+          - "1.20"
           - "1.21"
-          - "1.22"
-          - "^1"
+          - "oldstable"
+          - "stable"
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
           go-version: ${{ matrix.go-version }}
       - name: mkdir gocoverdir
+        # We can only use -test.gocoverdir for Go >= 1.20.
+        if: ${{ matrix.go-version != '1.18' && matrix.go-version != '1.19' }}
         run: |
           GOCOVERDIR="$(mktemp --tmpdir -d gocoverdir.XXXXXXXX)"
           echo "GOCOVERDIR=$GOCOVERDIR" >>"$GITHUB_ENV"
       - name: go test
-        run: go test -v -cover -timeout=30m -test.gocoverdir="$GOCOVERDIR" ./...
+        run: go test -v -timeout=30m ${GOCOVERDIR:+-cover -test.gocoverdir="$GOCOVERDIR"} ./...
       - name: sudo go test
-        run: sudo go test -v -cover -timeout=30m -test.gocoverdir="$GOCOVERDIR" ./...
+        run: sudo go test -v -timeout=30m ${GOCOVERDIR:+-cover -test.gocoverdir="$GOCOVERDIR"} ./...
       - name: upload coverage
+        # We can only use -test.gocoverdir for Go >= 1.20.
+        if: ${{ matrix.go-version != '1.18' && matrix.go-version != '1.19' }}
         uses: actions/upload-artifact@v4
         with:
           name: coverage-${{ runner.os }}-${{ github.job }}-${{ strategy.job-index }}
@@ -89,7 +133,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
-          go-version: "^1"
+          go-version: "stable"
       - name: download all coverage
         uses: actions/download-artifact@v4
         with:

CHANGELOG.md

@@ -6,7 +6,27 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased] ##
 
+### Compatibility ###
+- The minimum Go version requirement for `filepath-securejoin` is now Go 1.18
+  (we use generics internally).
+
+  For reference, `[email protected]` somewhat-arbitrarily bumped the
+  Go version requirement to 1.21.
+
+  While we did make some use of Go 1.21 stdlib features (and in principle Go
+  versions <= 1.21 are no longer even supported by upstream anymore), some
+  downstreams have complained that the version bump has meant that they have to
+  do workarounds when backporting fixes that use the new `filepath-securejoin`
+  API onto old branches. This is not an ideal situation, but since using this
+  library is probably better for most downstreams than a hand-rolled
+  workaround, we now have compatibility shims that allow us to build on older
+  Go versions.
+- Lower minimum version requirement for `golang.org/x/sys` to `v0.18.0` (we
+  need the wrappers for `fsconfig(2)`), which should also make backporting
+  patches to older branches easier.
+
 ## [0.3.5] - 2024-12-06 ##
+
 ### Fixed ###
 - `MkdirAll` will now no longer return an `EEXIST` error if two racing
   processes are creating the same directory. We will still verify that the path

go.mod

@@ -1,10 +1,10 @@
 module github.com/cyphar/filepath-securejoin
 
-go 1.21
+go 1.18
 
 require (
 	github.com/stretchr/testify v1.9.0
-	golang.org/x/sys v0.28.0
+	golang.org/x/sys v0.18.0
 )
 
 require (

go.sum

@@ -4,8 +4,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
-golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4=
+golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

gocompat_errors_go120.go

@@ -0,0 +1,18 @@
+//go:build linux && go1.20
+
+// Copyright (C) 2024 SUSE LLC. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package securejoin
+
+import (
+	"fmt"
+)
+
+// wrapBaseError is a helper that is equivalent to fmt.Errorf("%w: %w"), except
+// that on pre-1.20 Go versions only errors.Is() works properly (errors.Unwrap)
+// is only guaranteed to give you baseErr.
+func wrapBaseError(baseErr, extraErr error) error {
+	return fmt.Errorf("%w: %w", extraErr, baseErr)
+}

gocompat_errors_test.go

@@ -0,0 +1,26 @@
+//go:build linux
+
+// Copyright (C) 2024 SUSE LLC. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package securejoin
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGoCompatErrorWrap(t *testing.T) {
+	baseErr := errors.New("base error")
+	extraErr := errors.New("extra error")
+
+	err := wrapBaseError(baseErr, extraErr)
+
+	require.Error(t, err)
+	assert.ErrorIs(t, err, baseErr, "wrapped error should contain base error")
+	assert.ErrorIs(t, err, extraErr, "wrapped error should contain extra error")
+}

gocompat_errors_unsupported.go

@@ -0,0 +1,38 @@
+//go:build linux && !go1.20
+
+// Copyright (C) 2024 SUSE LLC. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package securejoin
+
+import (
+	"fmt"
+)
+
+type wrappedError struct {
+	inner   error
+	isError error
+}
+
+func (err wrappedError) Is(target error) bool {
+	return err.isError == target
+}
+
+func (err wrappedError) Unwrap() error {
+	return err.inner
+}
+
+func (err wrappedError) Error() string {
+	return fmt.Sprintf("%v: %v", err.isError, err.inner)
+}
+
+// wrapBaseError is a helper that is equivalent to fmt.Errorf("%w: %w"), except
+// that on pre-1.20 Go versions only errors.Is() works properly (errors.Unwrap)
+// is only guaranteed to give you baseErr.
+func wrapBaseError(baseErr, extraErr error) error {
+	return wrappedError{
+		inner:   baseErr,
+		isError: extraErr,
+	}
+}

gocompat_generics_go121.go

@@ -0,0 +1,32 @@
+//go:build linux && go1.21
+
+// Copyright (C) 2024 SUSE LLC. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package securejoin
+
+import (
+	"slices"
+	"sync"
+)
+
+func slices_DeleteFunc[S ~[]E, E any](slice S, delFn func(E) bool) S {
+	return slices.DeleteFunc(slice, delFn)
+}
+
+func slices_Contains[S ~[]E, E comparable](slice S, val E) bool {
+	return slices.Contains(slice, val)
+}
+
+func slices_Clone[S ~[]E, E any](slice S) S {
+	return slices.Clone(slice)
+}
+
+func sync_OnceValue[T any](f func() T) func() T {
+	return sync.OnceValue(f)
+}
+
+func sync_OnceValues[T1, T2 any](f func() (T1, T2)) func() (T1, T2) {
+	return sync.OnceValues(f)
+}